The following is about Akeson® HDI board electronic prototyping boards with bga pcb support Multilayer PCB related, I hope to help you better understand HDI PCB.
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						Item
					 
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						M-
					 
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						Layer count
					 
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						1-30 layers
					 
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						Material
					 
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						FR4(High TG, Halogen Free, high frequency), CEM1, CEM3,BT,Al base mateiral,and so on.
					 
					
						Supplier: SY,KB,ITEQ,Isola,Nelco,Rogers,Grance,Mitsui
					 
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						Maxpanel size
					 
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						32±20(800mm±508mm)
					 
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						Min width/space(min)
					 
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						4mil/4mil
					 
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						Max copper weight
					 
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						140um(4oz) for inner layer
					 
					
						175um(5oz) for outer layer
					 
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						Min machine drill size
					 
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						0.2mm(8mil)
					 
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						Via hole tpye
					 
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						Blind/Burried/plugged
					 
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						Thickness of finished board
					 
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						0.20-6.0mm
					 
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						Tolerance
					 
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						Registration of innerlayer to of innerlayer:±3mil
					 
					
						Accuracy of hole position:±2mil
					 
					
						Tolerance of dilled slot:±3mil
					 
					
						Tolerance of PTH diameter:±3mil
					 
					
						Tolerance of NPTH diameter:±2mil
					 
					
						PTH hole copper thichness: 0.4-2mil
					 
					
						Image to image tolerance:±3mil
					 
					
						Tolerance of etching:±1mil
					 
					
						Solder mask registration tolerance: ±2mil
					 
					
						Finished board : Thickness<=1.0mm: +/-0.1mm
					 
					
						Thickness>0.1mm:+/-10%
					 
					
						Outline router: +/-0.1mm
					 
					
						Outline Score: +/-0.2mm
					 
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						Color of solder mask
					 
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						Green, Black, Blue,Red, White and so on
					 
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						Surface freatment
					 
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						HASL,HASL Lead Free,OSP ,Immersion Gold, Immersion Ti, Immersion Sliver, Flash gold, Selective Gold plating(gold thicness up to 120u),Gold figers ,Carbon print, Peelabe Mask
					 
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						Hardness of solder solder
					 
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						>=6H
					 
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						Outline finished
					 
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						CNC, V-CUT, Punching
					 
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						Peel strength of line
					 
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						≥61B/in
					 
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						Warp and twist
					 
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						≤0.7%
					 
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